This patch fixes the Go frontend to issue an error for non-int
arguments to make. This implements a requirement of the language
spec. While we're here fix the value returned by the type method of a
builtin call expression to make, although this doesn't seem to make
any difference anywhere since we lower this to a runtime call before
the determine_types pass anyhow. There is already a test for this
error in the master repository: test/fixedbugs/issue16949.go. It just
hasn't made it into the gccgo testsuite yet. This fixes
https://golang.org/issue/16949. Bootstrapped and ran Go testsuite on
x86_64-pc-linux-gnu. Committed to mainline.